Compressor unloader



June 8 1926. 1,588,256

C. W. METZGAR COMPRESSOR UNLOADER Filed Nov. 5, 1925 INVENTOR kESZ GHI LMGZ an H 5 ATTOR EY Patented June 8, 1926.

UNITED STATES PATENT OFFICE. 1

OEES'I'EB w. METZOAB, OF EASTON, PENNSYLVANIA, ASSIGNOB TOINGEBSOLL-RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A. CORPORATION OFNEW JERSEY.

COMPRESSOR UNLOADEB.

' Application filed November 5 loading through the agency of a pluralityof clearance chambers controlled by a single clearance valve in asimple, cheap and eflicient manner.

Another object of the inventlon is to provide fluid pressure controlledmeans for limiting the movement of the clearance valve for eflectingstep by step regulation. Both the clearance valve and the stop arepreferably automatically responsive to receive pressure.

Further objects of the invention will hereinafter appear and the inventon 1s shown in one of its preferred forms in the accompanying drawingwhich 1s a dlagrammatic sectional elevation partly in long1tudinalsection and partly broken away showing the invention Referring to thedrawing, the cyllnder A shown as double acting is provided with the'piston B driven from any suitable englne or motor. The cylinder isprovided with sultable intake and discharge valves C and which may be ofthe plate type and the air or fluid to be compressed entering at the1nlet E is discharged at the outlet F connected as by means of the usualdischarge connection or pipe G to the receiver H.

The cylinder is provided with a plurahty of sets of clearance chambersJ, K and L, O, in this instance two sets of two clearance chambers eachbeing provided, and a single clearance valve P or Q is provided forcontrolling each set of clearance chambers. There may be as manyclearance chambers in each setas desired, but only two being illustratedin the drawing.

vThe chambers J and K controlled by the valve P are adapted to be placedin successive communication with one end of the cylinder through theports R and S and the port T while the clearance chambers L and O vareadapted to be placed in communication successively with the other end ofthe cylinder throu h the ports U and V and the port W. ese sets ofportsbeing respectivelyz controlled by the clearance valves P and Eachclearance valve is provided with a a, 1925. Serial 110. 86,494.

plunger X in the cylinder a and a compression spring 6 underneath theplunger tends to open the valve. Receiver pressure supplied through thepipes c or d holds the clearance valves closed, the; supply and releaseof receiver pressure being controlled bythe regulator Y. A secondcylinder e for each clearance valve-contains a plunger 7 having a stoppin 9 projecting into the cylinder a for limiting the movement of theclearance valve according of the plunger 7. A spring h beneath theplunger 7 tends to move the stop pin 9 outwardly and receiver pressureis admitted to the plungers f for forcing the stop inwardly. The pipes jand I: connect the stop cylinders a with the regulator Y as the receiverpressure increases through predetermined degrees. The apparatus and theregulator are so constructed that the clearance valve P is firstpermitted by the stop 9 to move a suflicient distance to open the port Rof the clearance chamber J as indicated in the drawings for the firststep of unloading, and upon a further increase of receiver pressure forthe next step of unloading the other valve Q is permitted by its stop 9to move a suflicient distance to place the clearance chamber L incommunication with the cylinder through the port U. At the next step ofunloadin pressure against the plunger 7, controlhng the stop for theclearance valve P, is released permitting the spring to retract the stopso that the clearance valve P-opens the port S and places the clearancechamber K in communication with the cylinder, and for the last step ofunloading, a similar operation is carried out for the clearance valve Qwhich opens the port V and places the clearance chamber 0 incommunication with the cylinder so that the cylinder is completelyunloaded.

Any. suitable regulator Y may be provided; in this instance theregulator casing Z having a valve chamber 0 for the auxiliary or pilotvalve 2 having the heads q and r. Receiver pressure is supplied from thereceiver H through the pipe 8 to the port If in the regulator casing sothat the space between the valve heads g and 1' is constantly open toreceiver pressure. One end u of'the valve chamber 0 is open toatmosphere, and

ports and passages lead from the valve to the position chamber o to thevalve chambers 12 of the main operating valves w having the heads a: andy. There are four of these main operating valves wall constructed in thesame manner and operating in the same manner, but only two of thesevalves and a portion of the third valve are shown. The two lower valves'20 shown in the drawing, controlthe pipes o and d leading respectivelyto the cylinders for the plungers X of the clearance valves P and Qwhile the two upper main operating valves w of the regulator control thepipes j and is leading respectlvely to the cylinders of the plungers fof the stops for the clearance valves tively.

The valve chambers '0 between the valve heads m and y are constantlysubject to receiver pressure through the-ports 3 connected by passages 4to the main receiver pipe 8 and the valves w are provided with shoes 5controlling ports 6 and 7 for supplying pressure to or releasingpressure from the P and Q respecclearance valve pipes 0, d, j and inrespectively. The main valves 'w are actuated by the alternate supplyand release of receiver pressure operating on the heads at and y.

The regulator Y is rovided with a diaphragm 8 for a .diap ragm chamber 9'to which chamber is connected the pipe 10 leading to the receiver. Apin 12 in the guide 13 which bears on the diaphragm,

, supports the weighted lever 14 pivoted at the pomt 15 to a bracket 16on the regulator casing. The pilot valve ;0 is hung by the valve stem 17from the lever 14 and the valve p is normally at its lowermost positionin the valve chest 0 so that receiver pressure passes to the'fourpassages 18, 19, 20 and 21 leading respectively to the left hand ends ofthe operating valves 10 so that these valves would normally be in theirright hand positions as the figure is viewed.

Four similar passagesfof which only two, 22 and 23, are shown connectthe right hand ends of the main operating valves m with points in thepilot valve chest 0 and these passages are normally open 'to atmospherethrough the open 'upper end 24 of the valve chest 0.

In the operation of the device, let it be assumed that the receiverpressure has. in

' creased sufiiciently to actuate the weighted actuated to the le lever14 sufliciently to lift the pilot valve 1 to the position shown in thedrawin in which case one o eratin valve '10 wi be and t e pipe 0 fromthe casing of the clearance valve P ,will be placed in communicationwith atmosphere through the ports 6 and 7 and the atmosphenc port 25 inthe regulator casing so that the first step of unloading will beeffected. As the pilot valve 17' is raised through successive stepsuncovering the passages 19, 20 and 21 respectively in the regulater andplacing them in communication .-withatmosphere, the four main valves towill be actuated one after the other to effect the succeeding steps ofunloading. When the pipe (1 is placed in communication with atmosphere,pressure behind the plunger X of the, clearance valve Q' is released andthe valve opens until its plunger strikes the stop 9. When'the pipe 7'leading to the plunger casing of the, stop 9 of the clearance valve P isopen to atmosphere by the regulator, the stop is retracted by its springand the clearance valve P moves to open the clearance chamber K to thecylinder for the third step of unloading. The final step is effectedwhen-the pipe 7*: controlling the stop for the clearance valve Q, is"open to atmosphere. The machine is automatically loaded step by step asthe valves operate in reverse order.

3. In a compressor unloader, the combination of a cylinder and piston,inlet and dischar e valves for the cylinder, a plurality of clearancechambers,-and" a single pressure. fluid automatically actuated clearancevalve, for successively controlling said plurality of clearance chambersfor step by step unloading. I

4. In a compressor unloader, the combination of a cylinder and piston,inlet and discharge valves for the cylinder, a plurality of sets ofclearance chambers, a single clearance valve for controlling each set ofclearance: chambers, and automatic pressure responsive means foractuating said clearance valves for step by step unloading.

5. In a compressor unloader, the combination ot a cylinder and piston,inlet anddischarge valves for the cylinder, a plurality of clearancechambers, a single clearance valvev controlling said plurality ofchambers, and a pressure fluid actuated stop for limiting the movementof said clearance valve.

6. In a compressor unloader, the combination of a cylinder and piston,inlet and dischar e valves for the cylinder, a plurality of c earancechambers, a single pressure fluid automatically actuated clearance valvefor successively controlling said plurality of clearance chambers forstep by step unloadmg, and a pressure fluid actuated stop for limitingthe movement of said clearance ling said plurality of chambers, both thevalve to control the said steps of unloading. valve and the stop beingautomatically re- 7 In a compressorunloader, the combinasponsive toreceiver pressure. 10

tion of a cylinder and piston, inlet and dis- In testimony whereof Ihave signed this 5 char e valves for the cylinder, a pluralityspecification.

of ciarance chambers, a. single clearance valve and stop for said valveion control CHESTER W. METZGAR.

